Casters find widespread usage across a vast range of industries requiring that equipment and materials be easily moved from place to place. Casters are available in a number of designs, each addressing a specific purpose or need. Common examples of light-duty casters are those used on shopping carts and office chairs. Heavy-duty casters are used to move bulk materials and heavy equipment. Casters used in both light and heavy-duty applications are available as swivel casters and straight-line or rigid casters.
In most instances, the ability to vary the height of the caster is not critical to the operation of the structure being supported by the caster. However, in the food service industry there is a special need for level food preparation, storage, and cooking surfaces, including range tops, ovens, refrigerators and preparation tables. For example, the following undesirable situations may result from unleveled kitchen equipment:    1) Unleveled refrigeration creates air gaps in doors and prohibits proper cooling, excessive energy costs, and potential spoilage;    2) Unleveled convection ovens create gaps in the door seals resulting in uneven and incomplete baking; and    3) Unleveled ranges result in the burners not heating evenly and creating “hot” spots in pots and pans.
Additionally, health codes require that commercial kitchens maintain strict standards of cleanliness and sanitation. Commercial kitchens ordinarily include drains and troughs for complete drainage of water and/or cleaning solutions from cleaning and sanitation of the cooking process or water and/or liquids from the cooking process. Accordingly, commercial kitchen floors are almost never level, drains and troughs notwithstanding, and usually have a series of slopes and/or grades. The vertical displacement and leveling mechanism must be easily accessible to a maintenance worker or installation person for adjustment purposes to account for unlevel kitchen floors.
The health codes requiring that heavy kitchen appliances be moved with regularity for cleanliness standards also will, in turn, require that the caster itself used to move the appliance also be easily accessible for cleaning. An accumulation of grease and other food particles will attract insects, molds and/or other vermin that will lead to unsanitary conditions, as well as creating a fire hazard. Accordingly, the adjustable caster for commercial kitchen appliances must be devoid of spaces, chambers, and parts where such matter can accumulate.